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Abstract:

In a method and to a device for treating a compound, such as a chemical
and/or organic and/or microorganism compound, which is carried by a
liquid, the liquid is driven axially through an axial inlet (21) into a
central inlet portion of a radial cavitation chamber (18) having a
peripheral outlet (30), such that the liquid is diverted into the central
inlet portion and flows into the radial chamber in various radial
directions towards the peripheral outlet; and the liquid flow conditions
between the inlet and the peripheral outlet of the radial chamber are
capable of generating cavitation bubbles or pockets (31) and subsequently
causing the collapse or implosion of the bubbles or pockets in order to
treat the compound at least partially.

Claims:

1. A method for treating a compound, such as a chemical and/or organic
compound and/or a micro-organism, carried by a liquid in which two
substantially radial faces (11, 19) arranged opposite each other delimit
between them a radial cavitation chamber (18), one of said faces having
an axial inlet orifice (21) formed axially in its central part and said
faces forming a peripheral outlet opening (30); in which the liquid
supplied axially through the axial inlet orifice (21) is deflected and
flows into said radial cavitation chamber (18) in various radial
directions toward the peripheral outlet opening (30); and in which the
thickness of said cavitation chamber (18), between said radial faces (11,
19), is selected such that it is between 0.1 and 0.25 times the diameter
of said axial inlet orifice (21) and is preferably 0.14; such that the
flow conditions of the liquid generate cavitation bubbles or pockets (31)
in the first part of the radial flow, around the central inlet orifice
(21) and that the cavitation bubbles or pockets (31) implode before they
reach the peripheral outlet opening (30), in order to treat said compound
at least partially in said cavitation chamber (18).

2. The method as claimed in claim 1, in which the distance between the
axis (5) of the central inlet orifice (21) and said peripheral opening of
said cavitation chamber (18) is selected such that it is more than twice
the diameter of said central inlet orifice (21).

3. The method as claimed in claim 1, in which the ratio between the
absolute pressure upstream of said cavitation chamber (18) and the
pressure downstream of this chamber is between 1.5 and 6.

4. A device for treating at least one compound, such as a chemical and/or
organic compound and/or a micro-organism, carried by a liquid,
comprising: a first element (3) having a substantially radial face (18)
and a substantially axial liquid-inlet orifice (21), and a second element
(10) having a substantially radial face (11), in which said radial faces
are arranged opposite each other so that they form between them a space
forming a radial cavitation chamber (18) having a peripheral outlet
opening (30), said axial inlet orifice of the first element opening out
into a central part of this cavitation chamber (18) opposite said radial
face (11) of the second element (10); the thickness of said cavitation
chamber (18), between said radial faces (11, 19), is between 0.1 and 0.25
times the diameter of said axial inlet orifice (21) and is preferably
0.14; such that the liquid which is supplied axially through the axial
inlet orifice (21) is deflected in the central inlet part and flows into
said radial cavitation chamber (18) in various radial directions toward
the peripheral outlet opening (30) and such that the flow conditions of
the liquid generate cavitation bubbles or pockets (31) in the first part
of this flow, around the central inlet orifice (21), and that the
cavitation bubbles or pockets (31) implode before they reach the
peripheral outlet opening (30), in order to treat said compound at least
partially.

5. The device as claimed in claim 4, in which said radial faces (11, 19)
delimiting said radial cavitation chamber (18) are parallel.

6. The device as claimed in claim 4, in which the distance between the
axis (5) of the central inlet orifice (21) and said peripheral opening of
said cavitation chamber (18) is more than twice the diameter of said
central inlet orifice (21).

7. The device as claimed in claim 4, in which said peripheral outlet
opening of said radial cavitation chamber (18) communicates with a
secondary chamber (124) connected to at least one outlet passage (120).

8. The device as claimed in claim 7, comprising a different treatment
means (121) associated with said secondary chamber, in particular an
emitting means generating ultraviolet radiation in said secondary
chamber.

9. The device as claimed in claim 7, in which the first element and the
second element comprise two walls (201, 202) which form a space between
them, one of the walls having a plurality of inlet orifices (204) for the
liquid and the other wall having a plurality of outlet orifices (206), so
as to form a plurality of cavitation chambers (209) in said space and
between said inlet orifices and said outlet orifices.

10. The device as claimed in claim 9, in which said inlet orifices open
out into an inlet collecting chamber (205) and the outlet orifices open
out into an outlet collecting chamber (207), where said walls can be
annular and concentric and are preferably cylindrical or concentric, or
flat.

11. The device as claimed in claim 4, in which said first element (3) has
a bevel on the edge of said axial inlet orifice (21), where this bevel is
rounded and has a radius between 0.1 and 0.5 times the distance between
said radial faces (11, 19) in the central part of the cavitation chamber
(18) or is in the shape of a truncated cone arranged at an angle between
30.degree. and 60.degree., preferably at 45.degree., and over a height,
in the axis of said axial inlet orifice (21), between 0.1 and 0.5 times
the distance between said radial faces (11, 19) in the central part of
the cavitation chamber (18).

12. The method as claimed in claim 2, in which the ratio between the
absolute pressure upstream of said cavitation chamber (18) and the
pressure downstream of this chamber is between 1.5 and 6.

13. The device as claimed in claim 5, in which the distance between the
axis (5) of the central inlet orifice (21) and said peripheral opening of
said cavitation chamber (18) is more than twice the diameter of said
central inlet orifice (21).

14. The device as claimed in claim 5, in which said peripheral outlet
opening of said radial cavitation chamber (18) communicates with a
secondary chamber (124) connected to at least one outlet passage (120).

15. The device as claimed in claim 6, in which said peripheral outlet
opening of said radial cavitation chamber (18) communicates with a
secondary chamber (124) connected to at least one outlet passage (120).

16. The device as claimed in claim 8, in which the first element and the
second element comprise two walls (201, 202) which form a space between
them, one of the walls having a plurality of inlet orifices (204) for the
liquid and the other wall having a plurality of outlet orifices (206), so
as to form a plurality of cavitation chambers (209) in said space and
between said inlet orifices and said outlet orifices.

17. The device as claimed in claim 5, in which said first element (3) has
a bevel on the edge of said axial inlet orifice (21), where this bevel is
rounded and has a radius between 0.1 and 0.5 times the distance between
said radial faces (11, 19) in the central part of the cavitation chamber
(18) or is in the shape of a truncated cone arranged at an angle between
30.degree. and 60.degree., preferably at 45.degree., and over a height,
in the axis of said axial inlet orifice (21), between 0.1 and 0.5 times
the distance between said radial faces (11, 19) in the central part of
the cavitation chamber (18).

18. The device as claimed in claim 6, in which said first element (3) has
a bevel on the edge of said axial inlet orifice (21), where this bevel is
rounded and has a radius between 0.1 and 0.5 times the distance between
said radial faces (11, 19) in the central part of the cavitation chamber
(18) or is in the shape of a truncated cone arranged at an angle between
30.degree. and 60.degree., preferably at 45.degree., and over a height,
in the axis of said axial inlet orifice (21), between 0.1 and 0.5 times
the distance between said radial faces (11, 19) in the central part of
the cavitation chamber (18).

19. The device as claimed in claim 7, in which said first element (3) has
a bevel on the edge of said axial inlet orifice (21), where this bevel is
rounded and has a radius between 0.1 and 0.5 times the distance between
said radial faces (11, 19) in the central part of the cavitation chamber
(18) or is in the shape of a truncated cone arranged at an angle between
30.degree. and 60.degree., preferably at 45.degree., and over a height,
in the axis of said axial inlet orifice (21), between 0.1 and 0.5 times
the distance between said radial faces (11, 19) in the central part of
the cavitation chamber (18).

20. The device as claimed in claim 8, in which said first element (3) has
a bevel on the edge of said axial inlet orifice (21), where this bevel is
rounded and has a radius between 0.1 and 0.5 times the distance between
said radial faces (11, 19) in the central part of the cavitation chamber
(18) or is in the shape of a truncated cone arranged at an angle between
30.degree. and 60.degree., preferably at 45.degree., and over a height,
in the axis of said axial inlet orifice (21), between 0.1 and 0.5 times
the distance between said radial faces (11, 19) in the central part of
the cavitation chamber (18).

Description:

[0001] The present invention relates to the field of treating compounds
such as chemical or organic compounds or species, or micro-organisms.

[0002] Unwanted chemical compounds are frequently found in water which has
been polluted by, for example, volatile compounds such as hydrocarbons or
chlorinated compounds (for example, trichloroethylene) or by not very
volatile compounds such as PCBs (polychlorobiphenyl), PCPs
(pentachlorophenol) used as fungicides or certain molecules which are
considered as endocrine disrupters. These bodies are usually carcinogenic
and can cause illness in animals and humans.

[0003] These unwanted bodies are currently destroyed or transferred using
a number of techniques including activated carbon adsorption,
thermolysis, electrolytic reduction, ultraviolet irradiation or oxidation
by chemical compounds such as ozone, peroxide or Fenton's reagent. Some
treatments combine several of these basic methods. In all cases, the
methods are expensive and awkward to implement.

[0004] The water can also contain living micro-organisms such as bacteria
or microscopic algae. It is often desirable to destroy them to avoid
pathological effects. Techniques equivalent to those used for chemical
compounds are used for this destruction, for example sterilization using
chloride or peroxide or ultraviolet irradiation.

[0005] To carry out some treatments, it has also been proposed to use
ultrasonic waves emitted into liquids which are to be treated and/or to
use cavitation inside the liquids which are to be treated and flowing in
Venturi tubes or in equivalent axial-flow tubes. Such arrangements are
described in the documents EP 1 738 775, US 2007/0280861, W02005/028375.

[0006] The documents U.S. Pat. No. 5,749,650, U.S. Pat. No. 5,899,564 and
US 2006/256645 describe treatment devices in which the liquid passes
radially through annular micro-slits formed between axially superposed
and axially adjustable rings. The liquid escapes through the slits,
forming radial jets which are dispersed in large peripheral evacuation
spaces, these jets causing turbulence in these spaces without any
cavitation pocket being formed.

[0007] The document U.S. Pat. No. 6,200,486 describes a device which
comprises an inner cylindrical wall having orifices and an outer
cylindrical wall, which form a large space between them. As in the
documents referred to in the paragraph above, the flow at the outlet of
the orifices is in the form of jets in this large space.

[0008] The document U.S. Pat. No. 4,585,357 describes a device which
comprises a radial micro-slit opposite which a deflecting wall is
installed at a great distance. Here too, the flow through the slit causes
dispersion jets.

[0009] The document JP 11 42432 describes a device in which two opposite
flows collide. The resultant flow flows away radially and is discharged
into a peripheral evacuation chamber, here too in the form of dispersion
jets.

[0010] The document DE 3728946 describes a device in which an axial flow
is deflected toward a radial chamber which has a peripheral opening. This
chamber is in the shape of a truncated cone and formed such that its
thickness reduces in the direction of the outside. Turbulence phenomena
occur only beyond the peripheral opening of the radial chamber, in the
large evacuation chamber.

[0011] The document JP 2008/207099 describes a device in which the liquid
is introduced axially into a blind hole and is evacuated through
divergent radial channels in the shape of truncated cones which are
formed in the wall of the blind hole, at a distance from the base. In
fact a Venturi-type mode of operation occurs in each divergent radial
channel in the shape of a truncated cone, axially thereto.

[0012] The object of the present invention is to produce a particular
cavitation effect which can improve the mechanical and/or chemical and/or
bacteriological effects and/or the effects on the micro-organisms, on the
compound or compounds carried in a liquid to be treated.

[0013] In order to achieve this object, the present invention is based on
a cavitation effect which causes the formation of bubbles or pockets of
vapor in a liquid under the action of reduced pressure and in which the
bubbles or pockets of vapor produced during this application of reduced
pressure then suddenly condense when the pressure rises again. Under
certain conditions, this rapid condensation, also called collapse, takes
place for periods of time between, for example, one ten thousandth of a
second and a microsecond depending on the initial size of the bubble or
the pocket, wherein this reaction can be sufficiently rapid that the
gases are compressed and heated to temperatures greater than, for
example, 2000° C., thus producing a plasma.

[0014] The present invention thus seeks in particular to increase the
combined effects of the intense turbulence which prevails in the collapse
zone of the cavitation bubbles or pockets and the very high speeds of the
wall of the latter; and/or to increase the effects resulting from the
plasma produced in the cavitation bubbles or pockets and capable in
particular of producing radiation in the liquid; and/or to destroy
compounds present in the cavitation bubbles or pockets; and/or to cause
the production of molecules, ions or species or chemical radicals which
can migrate into the liquid and act on the compounds carried in the
liquid; and/or to produce the intense sound waves in the liquid.

[0015] The subject of the present invention is first a method for treating
a compound, such as a chemical and/or organic compound and/or a
micro-organism, carried by a liquid.

[0016] This method is such that two substantially radial faces arranged
opposite each other delimit between them a radial cavitation chamber, one
of said faces having an axial inlet orifice formed axially in its central
part and said faces forming a peripheral outlet opening; that the liquid
supplied axially through the axial inlet orifice is deflected and flows
into said radial cavitation chamber in various radial directions toward
the peripheral outlet opening; and that the thickness of said cavitation
chamber (18), between said radial faces, is selected such that it is
between 0.1 and 0.25 times the diameter of said axial inlet orifice and
is preferably 0.14.

[0017] The flow conditions of the liquid thus generate cavitation bubbles
or pockets in the first part of the radial flow, around the central inlet
orifice. Also, the cavitation bubbles or pockets thus implode before they
reach the peripheral outlet opening, in order to treat said compound at
least partially in said cavitation chamber.

[0018] The distance between the axis of said central inlet orifice and
said peripheral opening of said cavitation chamber can be selected so
that it is more than twice the diameter of said central inlet orifice.

[0019] The ratio between the absolute pressure upstream of said cavitation
chamber and the pressure downstream of this chamber can be between 1.5
and 6.

[0020] The subject of the present invention is also a device for treating
at least one compound, such as a chemical and/or organic and/or a
micro-organic, carried by a liquid.

[0021] This device comprises a first element having a substantially radial
face and a substantially axial liquid-inlet orifice, and a second element
having a substantially radial face.

[0022] Said radial faces are arranged opposite each other so that they
form between them a space forming a radial cavitation chamber having a
peripheral outlet opening, said axial inlet orifice of the first element
opening out into a central part of this cavitation chamber opposite said
radial face of the second element.

[0023] The thickness of said cavitation chamber, between said radial
faces, is between 0.1 and 0.25 times the diameter of said axial inlet
orifice and is preferably 0.14.

[0024] The liquid which is supplied axially through the axial inlet
orifice is thus deflected in the central inlet part and flows into said
radial cavitation chamber in various radial directions toward the
peripheral outlet opening and the flow conditions of the liquid generate
cavitation bubbles or pockets in the first part of this flow, around the
central inlet orifice, and that the cavitation bubbles or pockets implode
before they reach the peripheral outlet opening, in order to treat said
compound at least partially.

[0025] Said radial faces delimiting said radial cavitation chamber can be
parallel.

[0026] The distance between the axis of the central inlet orifice and said
peripheral opening of said cavitation chamber can be more than twice the
diameter of said central inlet orifice.

[0027] Said peripheral outlet orifice of said radial cavitation chamber
can communicate with a secondary chamber connected to at least one outlet
passage.

[0028] A different treatment means can be associated with said secondary
chamber, in particular an emitting means generating ultraviolet radiation
in said secondary chamber.

[0029] The first element and the second element can comprise two walls
which form a space between them, one of the walls having a plurality of
inlet orifices for the liquid and the other wall having a plurality of
outlet orifices, so as to form a plurality of cavitation chambers in said
space and between said inlet orifices and said outlet orifices.

[0030] Said inlet orifices can open out into an inlet collecting chamber
and the outlet orifices can open out into an outlet collecting chamber,
where said walls can be annular and concentric and are preferably
cylindrical or concentric, or flat.

[0031] Said first element can have a bevel on the edge of said axial inlet
orifice, where this bevel can be rounded and have a radius between 0.1
and 0.5 times the distance between said radial faces in the central part
of the cavitation chamber or be in the shape of a truncated cone arranged
at an angle between 30° and 60°, preferably at 45°,
and over a height, in the direction of the axis of said axial inlet
orifice, between 0.1 and 0.5 times the distance between said radial faces
in the central part of the cavitation chamber.

[0032] The present invention will be better understood on studying
treatment devices with a cavitation chamber which are described by way of
non-limiting example and illustrated in the drawings, in which:

[0033] FIG. 1 shows a longitudinal section of a treatment device;

[0034] FIG. 2 shows a cross-section along the line II-II of the treatment
device in FIG. 1;

[0035] FIG. 3 shows an enlarged radial section of the cavitation chamber
of the treatment device in FIG. 1;

[0036] FIG. 4 shows a longitudinal section of an alternative embodiment of
the treatment device;

[0037]FIG. 5 shows a radial section along the line V-V of the treatment
device in FIG. 4;

[0038] FIG. 6 shows a longitudinal section of an alternative embodiment of
the treatment device;

[0039] FIG. 7 shows an internal side view of the treatment device in FIG.
6;

[0040]FIG. 8 shows an enlarged radial section of the central part of the
cavitation chamber in an alternative embodiment; and

[0041] FIG. 9 shows an enlarged radial section of the central part of the
cavitation chamber in an alternative embodiment.

[0042] A treatment device 1 shown in FIGS. 1 to 3 comprises a casing 2
which comprises two opposite shells 3 and 4 having a vertical axis 5 and
delimiting between them a radial cavity 6 which is formed between an
annular radial face 7 of the shell 3 and an annular radial face 8 of the
shell 4. The shells 3 and 4 can be identical and placed opposite each
other.

[0043] In the radial cavity 6, a spacer 9 is arranged which comprises a
disk 10 which has a radial face 11 bearing against the annular radial
face 7 of the shell 3 and which comprises a cylindrical peripheral part
12 which projects relative to the disk 10 and bears against the annular
radial face 8 of the shell 4.

[0044] The shells 3 and 4 have adjacent peripheral parts 13 and 14
connected by bolts 15 to fix them together and maintain the bearing
contact described above.

[0045] An O-ring 16 is installed between the periphery of the cylindrical
peripheral part 12 of the spacer 9 and the periphery of the cavity 6, in
the annular zone of the facing radial faces of the adjacent peripheral
parts 13 and 14 of the shells 3 and 4.

[0046] Inside its annular radial face 7, the shell 3 (first element) has a
recess 17 which delimits, with the radial face 11 of the disk 10 (second
element), a cavitation chamber 18, the base 19 of the recess 17 extending
radially, parallel to the radial face 11 of the disk 10.

[0047] The shell 3 has an axial passage 20 which has at the end a, for
example cylindrical, central orifice 21 which opens out axially into the
central part of the cavitation chamber 18, through the radial face formed
by the base 19 of the recess 17. The end of the duct 22 for supplying a
liquid 23 is engaged and fixed leaktightly in the passage 20, for example
by an annular packing gland system 24.

[0048] The shell 4 has an axial passage 25 which opens out axially, for
example through a central orifice 26 at the end, into the central part of
the secondary chamber 27 formed in the spacer 9, opposite the radial
cavitation chamber 18. The end of the duct 28 for evacuating the liquid
23 is engaged and fixed leaktightly in the passage 25, for example by an
annular packing gland system 29.

[0049] The disk 10 of the spacer 9 has a plurality of through passages 30
which open out, on the one hand, into the periphery of the radial
cavitation chamber 18 and, on the other hand, into the secondary chamber
27. The through passages 30 are regularly distributed over a
circumference so as to form a peripheral outlet opening of the radial
cavitation chamber 18. These through passages 30 can be formed by
cylindrical holes or circumferential slits.

[0050] The liquid 23 supplied by the supply duct 22 is thus introduced
into the central part of the radial cavitation chamber 18 through the
central orifice 21, is then deflected radially in this central part, and
then flows into the radial cavitation chamber 18 in various radial
directions toward the peripheral outlet opening formed by the through
passages 30. The liquid issued from the through passages 30 is then
collected in the secondary chamber 27, and then evacuated through the
evacuation duct 28.

[0051] The conditions of the radial flow of the liquid 23 in the radial
cavitation chamber 18, from the central inlet orifice 21 to the
peripheral through passages 30, are such that this flow is hydrodynamic,
that cavitation bubbles or pockets 31 appear in the first part of this
flow, around the central inlet orifice 21, and then collapse or implode
immediately before, preferably well before, these cavitation bubbles or
pockets 31 reach the peripheral outlet through passages 30.

[0052] The phenomenon of the creation and collapse of the cavitation
bubbles or pockets results from the effect of reduced pressures followed
immediately by elevated pressures. During the creation of the bubbles,
gases dissolved in the liquid tend to be released in these bubbles.
During the collapse, an adiabatic compression is produced which causes
very high temperatures and very high pressures in the bubbles which
implode.

[0053] The cavitation produced is a hydrodynamic cavitation which results
from the acceleration of the flow due to a reduction in its passage
cross-section followed by a gradual increase in said passage
cross-section in a virtually radial direction. This cavitation makes it
possible to create a very sudden rise in pressure in the condensation
zone or collapses, which causes an increase in the intensity of the
above-described effects for a given flow rate. Furthermore, the
particular shape of this device causes the phenomenon to occur with a
loss of pressure and hence a minimal expense of energy.

[0054] The cavitation pockets or bubbles 31 can include a main annular
pocket or bubble very close to the inlet orifice 21 and sticking to or
situated against the radial face 19 of the shell 3, supplied with gas
dissolved by the liquid which flows through. This main annular pocket or
bubble is split into smaller-sized pockets or bubbles which move away
from the center of the chamber and which condense, collapse or implode.

[0055] By virtue of the treatment device 1, the cavitation bubbles or
pockets 31 produced are able to at least partially treat the compound or
compounds carried by the liquid. This treatment can be chemical, thermal,
chemical and thermal and/or may be sonic as the cavitation phenomenon may
produce sound waves which radiate in the liquid.

[0056] The formation against the wall 19 and the collapse of the bubbles
or pockets of vapor 31 can be localized in a virtually predetermined
fashion and/or can be controlled. Because the thickness of the radial
cavitation chamber 18 is adapted relative to the cavitation bubbles or
pockets 31 produced, the cavitation affects all of the liquid to be
treated which flows into this chamber 18.

[0057] When the liquid such as water carries one or more chemical
compounds, specific chemical radicals or species can be formed in the
cavitation bubbles 31 produced and collapse, these specific chemical
radicals or species being capable of reacting with these chemical
compounds and producing other compounds. The chemical effects can cause
the destruction of compounds present in the bubbles, generally volatile
compounds initially dissolved in the liquid by the production of
molecules, ions or radicals which can migrate in the liquid and have an
action on the compounds which it carries. Among these actions, oxidation
by OH° radicals makes it possible to destroy dissolved molecules
which are difficult to remove.

[0058] When the liquid such as water carries one or more micro-organisms,
the cavitation bubbles 31 produced can make it possible to attack these
micro-organisms and/or films or accumulations of the latter, in order to
destroy, disperse or break them up by chemical or mechanical effects or
by intense pressure waves.

[0059] The flow conditions of the liquid in the cavitation chamber 18 of
the treatment device 1 can result from a subsequent dimensioning.

[0060] The thickness of the cavitation chamber 18 between the opposite
radial faces 7 and 19 can be between 0.1 and 0.25 times the diameter of
the central supply orifice 21.

[0061] The thickness of the cavitation chamber 18 can in particular be
0.14 times the diameter of the central supply orifice 21.

[0062] The distance between the axis 5 of the central supply orifice 21
and the circumference on which is formed the peripheral opening of the
cavitation chamber 18 determined by the through passages 30 can be more
than 2.5 times the diameter of the central supply orifice 21.

[0063] The ratio between the inlet pressure and the outlet pressure can be
between 1.5 and 6.

[0064] In one exemplary embodiment, the diameter of the supply orifice 21
can be 8 mm, the thickness of the cavitation chamber 18 can be 1.12 mm,
the distance between the axis 5 of the central supply orifice 21 and the
circumference on which is formed the peripheral opening of the cavitation
chamber 18 determined by the through passages 30 can be 30 mm.

[0065] According to one alternative embodiment shown in FIG. 8, said first
element 3 can have a rounded bevel 21a formed on the edge of the axial
inlet orifice 21 and joining the face 17. This rounded bevel 21a can have
a radius r which is between 0.1 and 0.5 times the distance between the
radial faces 11 and 19 in the central part of the cavitation chamber 18.

[0066] In another alternative embodiment shown in FIG. 9, said first
element 3 can have a bevel 21b in the shape of a truncated cone and
formed on the edge of the axial inlet orifice 21. This bevel 21b in the
shape of a truncated cone can be arranged at an angle of between
30° and 60°, and preferably at 45°. Its height h, in
the direction of the axis of the axial inlet orifice 21, can be between
0.1 and 0.5 times the distance between the radial faces 11 and 19 in the
central part of the cavitation chamber 18.

[0067] The bevels 21a or 21b can facilitate the formation of the
cavitation pocket 31 at their periphery.

[0068] With reference to FIGS. 4 and 5, it can be seen that a different
treatment device 100 is shown which comprises a cylinder 101 (first
element) which has a radial front face 102 in which is formed a
cylindrical recess 103 and which comprises a circular disk 104 (second
element) engaged at a distance in the cylindrical recess 103 and fixed
axially against three inner fingers 105 of a circular washer 106 bearing
against the radial front face 102 of the cylinder 101.

[0069] The stack formed by the cylinder 101 and the circular washer 106 is
engaged in the end of an outer cylindrical tube 107 such that the washer
bears against an inner shoulder 108 of this tube 107. The cylinder 101
has a peripheral shoulder 109 and fixing screws 110 which pass through
this shoulder and are screwed into the cylindrical tube 107 so as to fix
this stack. An O-ring 111 ensures the leaktightness between said stack
and the cylindrical tube 107.

[0070] The circular disk 104 is placed in the cylindrical recess 103 such
that a radial face 112 of this disk 104 and the radial base 103a of this
recess 103 form between them a cavitation chamber 113 of constant
thickness and that the periphery of the disk 104 and the periphery of the
recess 103 determine between them an annular through passage 114
determining a peripheral opening of the cavitation chamber 113 and
opening out inside the tube 107, between the inner fingers 105 of the
circular washer 106.

[0071] In order to ensure a constant thickness of the cavitation chamber
113, the radial base 103a of the recess 103 is provided with projecting
bulges 103b against which bears the radial face 112 of the disk 104,
these bulges 103b being placed at the periphery so as not to adversely
affect the flow of the liquid. The bulges 103b also center the disk 104
in the recess 103.

[0072] The cylinder 101 has an axial passage 115 which has a, for example
cylindrical, central orifice 116 at the end, which opens out axially into
the central part of the cavitation chamber 113. A connector 117 in which
the end of the duct 118 supplying a liquid is fixed leaktightly is
screwed into the passage 115.

[0073] The structure thus formed is such that the cavitation chamber 113
is equivalent to the cavitation chamber 18 of the treatment device 1.

[0074] The treatment device 100 can advantageously be connected in series
with another treatment device 100a as described below.

[0075] The other end of the cylindrical tube 107 is closed by a radial
wall 119 and has a lateral outlet opening 120 in the vicinity of this
wall 119. A duct (not shown) can be connected to the lateral outlet
opening 120 in order to evacuate the treated liquid.

[0076] The wall 119 is traversed leaktightly, via a seal 119a held by a
sleeve 119b, by an inner axial cylindrical tube 121 made, for example,
from quartz, a closed end 122 of which is situated in proximity to the
circular disk 104, the inner fingers 105 of the circular washer 106 being
extended by tips 123 for centering and holding the end 122 of the inner
cylindrical tube 121.

[0077] The inner tube 121 is connected to known means (not shown) which
can generate in this tube 121 ultraviolet radiation radiating in the
annular chamber 124 formed between the outer tube 107 and the inner tube
120.

[0078] A liquid such as water carrying one or more compounds to be treated
is thus, in a first step, treated by the treatment device 100 and then
immediately, in a second step, treated by the treatment device 100a in
the annular secondary chamber 124 by the ultraviolet radiation generated
by the inner tube 120, and then evacuated through the lateral outlet
opening 120. The radiation radiates throughout the annular secondary
chamber 124. As the disk 104 is made of quartz, the radiation can also
reach the annular through passage 114 and the cavitation chamber 113.

[0079] Such an arrangement is particularly advantageous when
micro-organisms carried by water need to be destroyed in order to treat
the latter and make it less polluted.

[0080] In an alternative, the means for generating radiation could be
placed around the outer tube 107.

[0081] In an alternative embodiment illustrated in FIGS. 6 and 7, a
treatment device 200 comprises an inner cylindrical wall 201 and an outer
cylindrical wall 202 which are concentric and delimit between them a
cylindrical space 203 of constant thickness which is closed at its ends
by any known means.

[0082] The inner cylindrical wall 201 has a plurality of inlet orifices
204 opening out, on the one hand, into the space 203 and, on the other
hand, into the internal space 205 of this wall 201, this internal space
205 forming a longitudinal inlet collecting chamber.

[0083] The outer cylindrical wall 202 has a plurality of outlet orifices
206 which open out, on the one hand, into the space 203 and, on the other
hand, into a peripheral space 207 delimited by a cylindrical peripheral
wall 208, the peripheral wall 207 forming a longitudinal annular outlet
collecting chamber.

[0084] The outlet orifices 206 are distributed around and at a distance
from the inlet orifices 204 so as to form a plurality of substantially
radial cavitation chambers 209 with substantially parallel flows, which
function respectively like the cavitation chambers described in the
preceding examples.

[0085] In the example shown, as shown in more detail in FIG. 7, the inlet
orifices 204 are distributed evenly spaced apart all around the inner
cylindrical wall 201 and longitudinally relative to the latter, and the
outlet orifices 206 are distributed evenly spaced apart all around the
outer cylindrical wall 202 and longitudinally relative to the latter,
offset by half a pitch relative to the inlet orifices 204,
circumferentially and longitudinally. The outlet orifices 206
advantageously have cross-sections which are considerably larger than the
cross-sections of the inlet orifices 204.

[0086] In the example shown, as shown in more detail in FIG. 6, the
internal space 205 forming an inlet collecting chamber is closed at one
end by a radial wall 205a and can communicate at its other end with an
axial inlet duct 210 which can be connected to a source of liquid to be
treated. The peripheral space 207 forming an outlet collecting chamber is
closed at one end by an annular wall 207a and can communicate with an
axial outlet duct 211 for the liquid treated in parallel in the
cavitation chambers 209, this axial outlet duct 211 being opposite the
axial inlet duct 210. The inner and outer cylindrical walls 201 and 202
are carried at one end by the wall 205a and at the other end by the wall
207a in leaktight fashion via O-rings 205b and 207b.

[0087] In other alternative embodiments, the walls 201 and 202 could have
different annular shapes, for example have the shape of a truncated cone,
or could be flat.

[0088] In another alternative embodiment, any one of the treatment devices
described above could be connected in series, the liquid outlet of one
device communicating with the liquid inlet of the following device.